Sync version with android gradle plugin

This CL starts loading version from android gradle plugin's
configuration file rather than data binding's configuration
file. This might be an issue in the future if we can support
additional build tools but for now, this will help simplfy
integration with tools.

Bug: 26560734
Change-Id: I1ea6f8e4716873b4ea84930e780c47eb7a6079ec
2 files changed